site: delegate fact to all the hosts

site: delegate fact to all the hosts

Before this patch we couldn't use --limit properly to only interact with
a particular set of hosts. We basically always required to have ceph-mon
role being played to properly get facts and then build the ceph.conf.

Now, the current running host will get the facts from the machines that
are not part of the current play. This is achieved with the help of the
new option delegate_facts, for more info see:
http://docs.ansible.com/ansible/latest/playbooks_delegation.html#delegated-facts

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1482067
Signed-off-by: Sébastien Han <seb@redhat.com>